ELECTRIC (CAR) UTILITY MANAGEMENT PROGRAM

“So I’m reading this Wall Street Journal article on surplus cars in storage and the thought occurs to me: If only these cars were all electric they could be used for grid load balancing while they were waiting to be sold. All those batteries could shift electric power from night to day.”

And in response to a reader question on how grid balancing would pay her for her personal auto, Joe Cresko, an AAAS Science Policy Fellow in the Energy Department's Office of Energy Efficiency and Renewable Energy wrote:

[I]t is based on the simple concept of peak (day) and off-peak (night) electricity rates. Charging the battery at night, when rates are lower, and feeding back to the electricity grid during the day would help utility companies by leveling demand. This type of rate structure is common in the power industry, and with the advent of a "smart grid" (an electricity distribution system based on more-advanced metering and communications technologies), residential customers would be able to benefit through significant efficiency increases.

Let's use Ms. Ivancic's own example (let's say 10 units at 10 cents per unit for $1), but consider connecting to the smart grid when at work to supply two units back to the utility. This would be of value to the utility (let's say at 15 cents per unit), since it would not need to increase power generation as much during the day to meet the increased electricity demand. In this example, charging at lower off-peak rates would reduce the daily cost of the work commute by 10 cents.

Hmm. That’s all well and good, except for a couple of minor points.

One. It assumes a 50% differential between on-peak and off-peak power generation. I’m not an engineering economist (that was 40 years ago), but that number seems a bit high.

Two. There is an energy conversion loss on both ends of the transaction. It isn’t much (a percent or so), but it’s there.

Three. There is no discussion of the infrastructure requirement at both ends of the transaction to perform the energy conversion. That isn’t cheap, especially since it has to exist for every car that is used. Who pays?

Four. Every battery has a limited lifetime (charge/discharge cycles) and must eventually be replaced. Will that ten-cent daily saving pay for the early replacement cost of the electric automobile’s battery?

Five. What are the chances that anyone would willingly give up 20% of their car’s capacity just prior to their commute home? Especially if the commute is a long one?

It’s a pleasant idea, but practical? I doubt it.

With apologies to the New Mexico State University Electric Utilities Management Program for the title.